You have some great advice and points. I've been trying to find a moto "school" around here but haven't had much luck... There is one about 2-3 hours from me so that's a bit of a long haul. I've been watching videos, reading articles and have picked up a great deal of info. Putting it to use is another thing.The part you said about not wanting to have to unlearn bad habits caught my eye: It runs with what I mentioned about spending your money on a school to learn to ride. If you rely on your friends to teach you, they will impart some of the good that they know, and some of the bad they dont even know is bad. I think once you get clutch use and starting the bike and getting it in and out of the truck or trailer down it is time for a school or at least some video from someone like Gary Semics.
Friends where racing is concerned can be invaluable, but unless they come with a real pedigree, you are going to do a lot of "unlearning" before either of you get too far. For instance if your friends have not done their best to steer a first time rider/mechanic away from a 2-3000 dollar 450 already then I think the best racing advice you should be taking with them is directions to tracks.
The most valuable learning tools for riding I currently know is a camera. Look at training vids, and use them to video your own riding.
My friends have a theory on price point. Has to work right, be used and beauty isn't important. They are experienced at rebuilding bikes and such so that will be a huge help.
Why do you say "steer a first time rider/mechanic away from a 2-3000 dollar 450 already then I think the best racing advice you should be taking with them is directions to tracks."? From what I understand that is a good price point for an older model